offset = int(input())
text = input()
result = ""
for char in text:
    if char.isalpha():
        if char.isupper():
            base = ord('A')
        else:
            base = ord('a')
        new_char = chr((ord(char) - base + offset) % 26 + base)
        result += new_char
    else:
        result += char
print(result)